Capacity analysis of mimo ad hoc network with stream number selection

We study the problem of stream number selection in an ad hoc multiple-input multiple-output (MIMO) network, where there are a number of co-existent MIMO transmitter-receiver pairs. We assume that there is no channel state information (CSI) at the transmitters, and the receivers use single-user detection. It is shown that the link capacities at high signal-to-noise ratio (SNR) is mainly limited by the number of degrees of freedom available at the receiver side. In general the number of streams per transmitter should not be more than N_tau/L when the interference level is high, where N_tau is the number of receive antennas and L is the number of simultaneous links. When the interference level is low, the number of streams should be set equal to the number of transmit antennas.